This is likely delayed from when most people actually saw the series, though without subscribing to HBO I had to wait till it came out on Netflix. Given all the publicity the series got I am surprised I was able to stay away from any spoilers so I'll try and return the favor and not give away anything too much here.
Not that this series is one of those with a big twist at the end or a significant change in direction. It doesn't. In its simplest sense, True Detective is a fairly standard police procedural with two mismatched homicide detectives at its center. From there however it moves in less typical directions.
The pacing, which is likely what has been criticized the most, is deliberate. Not slow mind you but deliberate as a film like Silence of the Lambs is. This may be too slow for people expecting a CSI like pace with the story wrapped up neatly in an hour. Though I shouldn't necessarily disparage all viewers with such a broad brush as there are many quality long form dramatic shows in existence now--something that couldn't have been said 10 or so years ago.
The story itself centers around a number of murders seemingly connected by religion, politics and the Louisiana coastline. If there is a third main character in this series it is Louisiana itself. Hot, humid, decaying, trashy, destitute, racially charged storm ravaged, Louisiana exerts its influence in every scene. From old, overgrown, 300 year old forts to sprawling industrial refineries to trailer parks buried deep in the woods, there is no scene here where you don't know you are in Louisiana.
Matthew McConaughey is the star here despite Woody Harrelson's extremely good work. McConaughey is a nihilistic cop with a dark background including a long time undercover position and the death of a young daughter. His hard turns had laid waste to his outlook on life leaving him viewing humanity as more of an accidental virus in need of extermination than anything worthwhile saving. No matter how dark his outlook, you suspect that there is some glimmer of light at his core--afterall...if your outlook is truly that dark and your true view of humanity is of that as a committed anti-natalist then you should be first in line for carbon-monoxide sleepy train. McConaughey has put forth some great performances of late and this stands right with Dallas Buyers Club.
Structure wise the series moves back and forth between the present and past as McConaughey and Harrelson's characters are interviewed by current investigators interested in a recent murder that bore similarities to the ones that they had thought solved more than a decade earlier. Then when the interview concludes and brings the viewer up to date, it moves forward from there staying in the present.
There are numerous "cool" scenes in the series--the six minute long single take of McConaughey running through a series of Texas projects, the numerous stick figure paintings and models left behind by the killer, the whole "Who is the Yellow King?" meme, etc. The initial season will live on as an influence on both TV and Film for quite some time as it helps continue to show that smart, dark, long form media is a viable product. Just don't believe anyone who says that Rust (McConaughey's character) is a true nihilist. While he might spout the dialogue worthy of one, the writers leave you with a great glimmer of light in the last two lines of the film which, if you really listen to and understand, recasts Rust's dialogue as of one of profound hurt and emotional anguish vs. one of a true pessimist.
If you have not seen this series and you at all consider yourself a consumer of intelligent fiction of any kind you are missing out and would be well served by viewing this eight episode series.